Gas turbine temperature control



Aug. 14-, 1951 A. w. ORR, JR 2,564,127

GAS TURBINE TEMPERATURE CONTROL Filed May 23, 1947 3 Sheets-Sheet l SPEED- GOVERNOR 76 I'iy I Orr Jr:

41- Top/V5 Y A. W. ORR, JR

GAS TURBINE TEMPERATURE CONTROL Aug. 14, 1951 3 Sheets-Sheet 2 Filed llay 23, 1947 .14. W Orr J1:

' INVENTOR.

Aug. 14, 1951 A. w. 0121?, JR 2,564,127

' GAS TURBINE TEMPERATURE CONTROL Filed Hay 2:5, 194? 3 Sheets-Sheet s Fray. 4

11 "(Orr Jr'- INVENTOR.

NT'TOKNE'Y Patented Aug. 14, 1951 UNITED STATES PATENT OFFICE GAS TURBINE TEMPERATURE CONTROL Andrew William Orr, Jr., Detroit, Mich., assignor to George M. Holley and Earl Holley Application May 23, 1947, Serial No. 758,016

Claims.

The object of this invention is to control the temperature in a gas turbine.

It is also the object of this invention to control the fuel flow with reference to the air flow in a combustion chamber of an engine.

Fig.1 shows the control adapted to control the load by increasing or decreasing the pitch of the propeller or alternatively decreasing or increasing the area of the conical outlet for the exhaust gases leaving the gas turbine.

Fig. 2 shows the control adapted to control the fuel at any selected pitch of the propeller or at any selected position of the cone in the gas outlet.

Fig. 3 shows an alternative temperature correction means to correct both for the temperature of the air and of the fuel; and

Fig. 4 shows the device controlling a variable pitch propeller.

In Fig. 1, I8 is the air entrance. I2 is a pitot tube in the air entrance I8. I4 is a diaphragm responsive to the pressure difference derived from the pitot tube I2. nected to the impact pressure side of the pitot tube I2. I8 is a barometric element located in a chamber 28 and controlling a V shaped valve 22 located in the outlet from the venturi I6. 24 is a pipe leading from the valve 22 to the outlet from the venturi I6. 24 is a pipe leading from the valve 22 to the low pressure side of the pitot tube I2. 26 is the chamber to the left of the diaphragm I4 and is connected through the pipe 28 to the impact side of the pitot tube I2. 30 is the chamber to the right of the diaphragm I4 and is connected through the passage 32 to the throat of the small venturi I6.

A small pin 34' engages with the left hand side of the small diaphragm 36. A small pin 38 engages with the right hand side of the small diaphragm 36 and with the left hand side of the large diaphragm I4. 48 is a small pin which engages with the right hand side of the diaphragm I4 and with the left hand side of the small diaphragm 42.

Pipe 44 connects with the low pressure side of the pitot tube I2, with the chamber on the left hand side of the diaphragm 36 and with the right hand side of the diaphragm 42. Pipe 46 connects with the chamber on the right hand side of the small diaphragm 36, with the left hand side of the small diaphragm 42 and with the pipe 24 which communicates with the low pressure side of the pitot tube I2.

Servomotor valve 48 engages with the right hand side of diaphragm 42 and with the left hand side of fuel responsive diaphragm 58. Chamber I6 is a small venturi con- I 52, to the left of diaphragm 58, engages with the pipe 54 which is the main fuel outlet leading to the fuel nozzle. Chamber 52 also communicates with a small pipe 56, past the air inlet temperature valve 68 to the passage 58. Passage 58 connects with the passage 62, to the right of the fuel diaphragm 58 The bellows 51' and the temperature responsive bulb 59', are connected together by the passage 55. The increase in temperature of the bulb 59 thus moves the valve 68 to the right. Passage 64 connects the chamber 62 to the small chamber 66, to the left of the small pin 34. Chamber 62 connects with the outlet passage 68, through the passage 69, leading from the speed governor I8, which speed governor received its fuel from the fuel pump 12. This speed governor is shown driven by a flexible drive shaft II which in its turn is driven by the shaft 98 of the gas turbine. Speed governor I8 returns its excess fuel through the fuel bypass 14 to the fuel inlet 16.

A cam 16, moved by the lever 88, raises and lowers the fuel orifice 82. A fuel needle 84, which enters the fuel orifice 82, is positioned relative to the orifice 82 by the bellows 86. The bellows 86 are connected to the temperature bulb 88 which is located in the outlet from the air compressor 98. The fuel flow past the orifice 82, past the fuel needle 84 emerges into the fuel passage 54 and discharges into the fuel nozzle 92-434. This fuel is consumed by the air admitted to the air en trance I8 and compressed by the air compressor 98. The gas turbine 96 is rotated by the fuel burning in the air. The shaft 98 is thereby rotated. The shaft 98 rotates the speed governor I8, through the flexible shaft II, and the fuel pump I2, and also the oil pump I88 by gears, not shown.

Oil pump I88 takes oil from the oil tank I82 and delivers the oil past the servomotor valve 48 through the pipe I84I85 and directs the oil under pressure to the chamber I86, to the right of the piston I88. Small opening H8, in the piston I88, permits oil to flow back to the tank I82, through the passage II2. Relief valve'I I4 is provided to limit the pressure in the passage I84.

The rod I I6 is connected so that when it moves to the left the pitch of the propeller is automatically increased. Alternatively it is connected so as to move the conical valve II8 to the right. In either case the tendency will be to increase the fuel/air ratio and therefore the temperature will rise. As shown the rod II6 engages with the link I54 which is pivoted on the pin I56. Link I58 connects the lever I54 with the lever I68. Lever I68 is mounted on the shaft I62. Shaft s earer 5 :52 carries the lever I64 which carries the cone 59 0. Spring lit engages with the piston I08 which tends to move the cone H0 into the open- In Fig. 2 similar parts are marked with similar numbers and have the same function.

Howevenin this case the servomotor valve 4c is connected through the passage I46 to the chamber I22, to the left of the diaphragm 524. Balance valve I26 is carried by the diaphragm I24. A spring I28 pushes the valve iih to the right, in which position the valve I28 opens and allows fuel to flow up the pipe 54 to burners 84. In this cm there is no speed s vernor provided and the fuel pump 12 dismarges fuel past the pressure relief valve I88 to the fuel orifice 82 and past the fuel needle 84.

The pressure relief valve I30 is partially supported by the spring I32 and also by the pressure in the pipe 54 transmitted through the passage I54 to the underside of the valve I80. Just before the fuel passes the fuel orifice 82 fuel flows past the zero torque fuel adjustment needle 86.

Fuel flows along the pmage I38, past the pilot valve I48, to the balance valve I26. Pilot valve I48 is provided with a small opening I42 in its center. The fuel flowing through the small opening I42 flows up along the passage I44, past the servomotor valve 48, down the passage I40 to the chamber I22. Pilot valve I40 Is carried by the diaphragm I48, which diaphragm is pushed to the right by the spring I88.

In Fig. 3, between the temperature responsive bellows II, is inserted temperature responsive Barometric washers I08. The chamber I62 surrounding the bellows 51 is now connected through the w: e IE4 with the fuel chamber 52.

In Fig. 4 the lever I54, controlled by servovalve 48 of Pig. 1 and slave motor piston I88, controls the lever IIi which is an extension of lever I04. Lever I18 en ages collar III of the variable pitch propellers I18 and Ill.

Operation InFig.1thecam|8isplacedinaselected position by the pilot. The pressure differences set up by the pitot tube I2 and the small venturi It move the servomotor valve 48 to the right. Bervomotor valve 48 is moved to the left by the diaphragm 58 which responds to the drop in pressure to the fuel flowing past the restriction l2 and past the needle valve 84.

Servomotor valve 48 controls the position of the piston I88. when the servomotor valve 48 moves into the position shown pump I80 applies pressure to the right hand side of piston I08 pushingtberod IIttotheleft. Rod IIiinlts turn rotates the lever I54 which causes the lever I" to also rotate which moves the cone III into the direction of closing. when the temperature istoolowandmore airisadmittedthatis more than 8 called for by the fuel adjustment I8, the valve 48 restricts the flow through the passages Ill-I85. Piston I08 then returns to the right under the influence of spring Ill and the cone II8 moves into the direction of opening. Bervomotor valve 48 thus controls the motion of the slave piston I88. 7

As a result the cone. II8,is adjusted automatically in response to the position of the cam 18. The speed governor 18. when the speed increasenredncesthemelflowandthus reduces the temperature in the combustion chamber.

In Fig. 2 the variation of fuel flow and the variation in air now are weighed the one against the other. The weight of the air is determined by the pressure of the air and by the temperature of the air. The pressure of the air is applied to the bellows I8, and the temperature of the air is applied to the bellows 51 so that the valve 48 is adjusted to give the selected fuel/air ratio. when selected, fuel/air ratios will result in a definite increase in temperature when the gases strike the gas turbine 86. However, it is the sum of the temperature of the air entering the combustion chamber plus the temperature rise in the combustion chamber which determines the maximum temperature of the gases striking the gas turbine 06. Hence, the bulb 88, which responds'to the temperature of the compressed air, moves the needle 84. As the needle 04 enters the fuel orifice 82 a given flow of fuel causes a bigger pressure drop and therefore pushes the diaphragm 50 to the left. As the servomotor valve 48 moves to the left the valve I40 tends to close and the fuel flow is diminished and equilibrium is reached with a lower fuel/ air ratio.

As a result the fuel flow is controlled by the cam 18 to give the desired temperature.

In Fig. 3 when the density of the fuel falls, due to a rise in its temperature, the valve 58 is moved to the left due to the contraction of the elements I60. This maintains the fuel/air ratio constant when the fuel/air ratio is measured on a weight basis. Otherwise when the density of the fuel falls the mixture would tend to get lean.

What I claim is:

1. Temperature selecting means for the combustion chamber of a combustion engine having an engine driven air compressor delivering air to said air compressor, a source of fuel under pressure, a fuel passage, an adjustable fuel restriction therein, manually adjusting means for varying said fuel restriction, temperature responsive means located in the outlet from said air compressor, an additional fuel restricting means also located in said fuel passage, said additional fuel restricting means being adapted to be moved by said temperature responsive means, a fuel outlet from said fuel restricting means leading to said combustion chamber, an air entrance to said air compressor, air flow indicating means located therein, a moving wall responsive to air flow and having a chamber on one side of said moving wall connected to the pressure side of said air indicating means, a. chamber on the other side connected to the low pressure side of said air indicating means, a second moving well, said second moving well being responsive to fuel flow and having a chamber on one side of said moving wall connected to the pressure upstream of saidfuel restriction, a second chamber on the other side of said second moving wall and connected to the low pressure downstream of said fuel restriction, a servomotor valve operatively connected to both moving walls whereby an increase in air flow moves the valve in one direction and an increase in fuel flow moves the valve in the other direction, a slave motor dominated by said servomotor valve, load control means for said engine, mechanism connecting said slave motor to said load control means so that the load is decreased to prevent excessive combustion chamber temperatures.

2. A device as set forth in claim 1 in which there are additional temperature responsive .gether, a restricting valve in said bypass operating means for said valve connected to said temperature responsive means.

3. A device as set forth in claim 1 in which there is an engine driven speed governor including a speed responsive fuel flow control valve, a fuel entrance to said governor, a fuel exit for said governor connected to said passage so as to reduce the fuel flow to said manually controlled restricting means so as to regulate the engine speed at a preselected speed.

4. A device as set forth in claim 1 in which the air flow indicating means includes a bypass from the pressure to the suction side of said indicating means, a small venturi therein, a passage from the throat of said venturi to the low pressure side of said first moving wall.

5. A device as set forth in claim 1 in which the air flow indicating means include a bypass from the pressure to the suction side of said indicating means, a small venturi in said bypass, a passage from the throat of said venturi to the low pressure side of said first moving wall, a valve restricting the air flow through said venturi, atmospheric pressure responsive means adapted to move said valve in the closing direction at high altitudes.

ANDREW WILLIAM ORR, JR.

REFERENCES CITED UNITED STATES PATENTS Name Date Number e Chandler Sept. 4, 1945 

